Temporomandibular joint disorder, more commonly known as TMJ, is a condition that affects the joint that opens and closes the mouth. The temporomandibular joints, located in front of the ears, attach the lower jaw to the skull and control mouth movement. This painful disorder can affect either the joint or muscles that surround it. The most common symptoms of TMJ are pain or loss of movement in the jaw, earache, headache, popping noises when opening and closing your mouth, facial pain and dizziness, among others. Exercising one's jaw increases blood flow and oxygen to the joint and muscles, helping to rejuvenate them.
Additionally, athletes have long included jaw exercise in their workout regimens. However, facial muscle tone shouldn't be overlooked. Boxers, football players and other contact sport athletes do so to prevent knockouts and concussions by building a more muscular sheath surrounding the skull. In that same vein, toned jaw muscles help tighten one's facial skin and to better define the jawline. The condition of jaw muscles also known to impact the ability to eat harder foods without discomfort or strain. Additionally, use of training equipment on the jaw, especially compressive equipment has been linked to increased blood flow in the gums and, possibly, a consequent resistance to gingivitis.
To this end, inventors have developed jaw exercise equipment to provide resistive training to muscles. One such device is the “Device for Strengthening the Gums” filed by Mr. K. Kuhn on Jul. 18, 1927 and on May 21, 1929 receiving U.S. Pat. No. 1,714,029 directed to a device including two plates, “spread asunder by spring-pressure and designed to take up chewing pressure.” Separated by a helical spring set inside of a pivoting hinge, the plates provide a yielding resistance against which the user can assert pressure using the jaw muscles. Unfortunate positioning of the spring at the opening of the mouth has resulted in users pinching lips and tongues.
U.S. Pat. No. 1,851,865 issued to Mr. P. G. Ptacek on Mar. 29, 1932 seeks to eliminate the helical spring in favor of a U-shaped leaf spring, serving both as a resilient member and as the hinge as opposed to the Kuhn arrangement, Having a rubber lined channel for each of the upper and lower jaws of teeth, the Ptacek device enjoys the additional benefit of allowing fore and aft adjustment of the channel to receive the lower teeth moving the lower jaw either into and out of the mouth to adjust occlusion.
The first all elastomeric device of note in this field is not for exercising but for protecting teeth from impact for such as “boxers, football players, and others engaged in sports or other pursuits, to prevent injury to the lips and teeth, and to prevent the user from becoming unconscious or damaged as a result of a blow to the jaw”; so it is that James B. Poindexter describes his invention in U.S. Pat. No. 2,192,558 issued on Mar. 5, 1940 for a “Tooth Guard and Jaw Protector.” The device was a formed block of vulcanized rubber to receive the teeth of the upper and lower jaws being capable of “sufficient yielding to prevent damage to the cusp and crown portions of the teeth [and to] positively hold and retain the teeth in interlocking relation.” The guard was only helpful so long as the athlete could breathe sufficient volumes of air through the nose, as it had no means for air to enter or leave the mouth.
Elastomer made the transition from mere protective packing material to the resilient member in a jaw exercising device at the hands of John H. Morris in his Jul. 15, 1941 patent for a “Tooth and Gum Exerciser.” The tooth and gum exerciser comprised a body “of substantially H-shaped cross-section . . . and arcuate longitudinal countours . . . to fit one half of the mouth from the front to the rear and to embrace both the upper and lower teeth and gums on that side of the mouth . . . . The device is formed of rubber or other resilient material.” Formed as a half mouth dam, the device did not prevent user respiration and is generally regarded as advancement in the art.
Victor H. Carpenter added respiration ports in the monolithic block of Dr. Poindexter to create the “Tooth Guard” U.S. Pat. No. 2,521,039 issued on Mar. 16, 1949 teaches. Incorporating the H-shaped arcuate channel of Morris, the Carpenter Tooth Guard had, as its object, “to provide in a guard of this type, adequate passageways for flow of air to the lungs of the wearer in breathing, and to prevent closing of the wearer's jaws sufficiently to close the passageways.”
In the last fifty years, such advances as have been made relate principally to the employment of materials rather than vulcanized rubber. A good example of this substitution of elastomers for the vulcanized rubber of the forties is the “Interocclusal Appliance and Method” described in U.S. Pat. No. 8,316,859 to Frank M. Lesniak issued on Nov. 27, 2012. The abstract asserts, “[a]n interocclusal appliance is formed from a single polymer material composition as one unitary piece or from multiple polymer material compositions as a two-piece preform. The two-piece preform includes a base material and an impression material that has a softening point lower than the base material. Teeth are received into the heat-softened impression material, so as to contour the impression material. A portion of the impression material also may contour to a portion of the user's palate. In certain embodiments, substantially no polymeric material contacts the front surfaces of the front teeth, leading to greater comfort and better air flow between front teeth. In still another embodiment, the appliance fits over front teeth only and no polymeric material contacts the maxillary molars.
Isometric exercise or isometrics are a type of strength training in which the joint angle and muscle length do not change during contraction (compared to concentric or eccentric contractions, called dynamic/isotonic movements). Isometrics are done in static positions, rather than being dynamic through a range of motion. Unfortunately, the elastomeric devices do little more provide the opportunity for isometric exercise as the user compresses a thin layer of elastomer, resulting in development of the muscles of the jaw only at a single point of extension or flexure and fails to work muscles through a range of motion. Only the Kuhn and Ptacek devices are able to present resistance through a range of motion. These, however, suffer from other inadequacies due to their geometries and spring arrangements that simply afford more dangers of harm than promise of tone and strength. What is missing in the art is a true jaw exerciser provided a range of resistance in isotonic exercise of the muscles of the jaw.